1. Field of Art
This invention relates to an agricultural furrow opening tool for planting seeds in paired rows.
2. Description of Prior Art
It is commonly desirable to perform seeding and fertilizing operations in one pass over a field to be planted. This trend has continued with advancements in low-till and no-till planting implements. Ground working tools have evolved for planting in these no-till and low-till conditions and for improving seed bed utilization. Presently a wide variety of types of ground working tools are available for planting in various soil conditions. These ground working tools are generally categorized as disc types or hoe types. Existing ground working tools designed for working well in certain conditions are not always suitable in other conditions.
For many types of crops such as cereals and oilseeds, planting of the seeds is efficiently achieved by bulk metering. The seeds become generally evenly spaced as seeds are distributed at a seeding rate through distribution lines to ground working tools by which they are planted in rows in the soil. The rows are spaced to achieve the best possible utilization of the soil area, however other factors effect row spacing, such as the need to allow field trash to pass between ground working tools while they are pulled through the soil for planting. This has led to the development of paired row seeding tools which each plant two rows of seed to achieve good seedbed utilization with fewer tools thus also allowing good field trash flow. It is also common that these tools are also designed to simultaneously place a fertilizer row between the seed rows. Research has shown that precise placement of seed at particular spacing along side an appropriate amount and type of fertilizer improves yields.
One such ground working tool is provided according to U.S. Pat. No. 5,025,736 by Anderson. A hoe ground working tool is disclosed which has a narrow leading end for opening a furrow for placement of fertilizer. Trailing the leading end is a press plate which tapers to a wider rearward end from a forward end centered behind the leading end. The press plate is also angled downwards and rearwards from the leading end. It acts to press down on an area wider than the furrow opened for fertilizer for closing the fertilizer furrow and preparing a firm seedbed. It has a wear strip along each side of the press plate which is claimed to extend beyond the rear end of the press plate so that grooves are formed in the seed bed. A seed distribution tube carries seed to a divider disposed behind the press plate which randomly divides the seed into two streams directing the seed to the sides of the seed bed and into the laterally spaced grooves. However it is known that in some soil conditions, particularly that known as heavy soil, more aggressive action is required to close the fertilizer furrow. If this furrow remains unclosed and no level seedbed is formed, then a large amount of seed falls into the fertilizer furrow rather than being placed to each side. Fertilizer too close to the seed is toxic to the seed as it germinates and they will die.
A similar hoe ground opener is disclosed in U.S. Pat. 4,674,419 by Kopecky. An auxiliary press plate is disclosed which has somewhat more aggressive wings for forming seed furrows. The press plate has a main flat central surface which in operation is also angled downwards and rearwards from a leading end to press down over a fertilizer furrow created by a preceding narrow opener. The wings have inner surfaces that taper laterally and downwardly from the central surface and outer surfaces that are generally vertical. The wings inner surfaces also converge toward the rear of the plate and thus in operation push some soil inwardly to close the fertilizer furrow. Such an arrangement of surfaces is more aggressive at closing a fertilizer furrow. However in conditions of heavy soil, when the soil is wet it tends to be bulldozed by opener surfaces that are too aggressive or restrict passage of the soil. The soil can bind to a furrow opener's surfaces. In these conditions ground tools do not properly cover the fertilizer furrow and seed and fertilizer are scattered ineffectively. A planting tools fertilizer delivery openings can even become blocked by soil that is pushed and builds up in front of the seed furrow forming surfaces. In fact, the Anderson patent discloses using low friction plastic as a press plate to prevent binding of soil. This can lead to a costly construction.
Flexicoil Ltd. also discloses furrow openers as shown on pages 45-47 of their Product Book (volume 2). Two different openers are promoted for use in different soil conditions. For heavy soil an HS paired row opener is promoted having a main central surface that runs level in operation, and wings that form a seed furrow on each side of a fertilizer furrow. Since the main surface runs level, it does not tend to restrict passage of heavy wet soils. It produces paired seed rows that are spaced apart about 2.5 inches. However if such an opener is made with wings more widely spaced for wider space between seed rows, it has been found that this shape may not perform aggressively enough to properly close the fertilizer furrow in all conditions. An LS paired row opener is promoted for use in light soils. It does not include a central pressing surface and rather the wing surfaces converge at a central edge forming bottom surfaces in an inverted V arrangement. The central edge runs generally horizontal. The wings also have leading surfaces that face slightly inward and downward for gathering soil and directing it inwards and downwards as it passes beneath the opener, closing the fertilizer furrow. This shape however has found to be too aggressive for heavy soils which becomes stuck between the wings.
In heavy wet soils particularly, the soil tends to bind to seeding tool surfaces between paired furrowing wings when those surfaces intersect at small obtuse angles or have little or no radius between them so the intersection forms a more distinct edge. Soil binding is more problematic especially when the intersection of the soil deflecting surfaces is angled or transverse to the direction of travel, and even when the angle between surfaces is moderately obtuse. Even with a surface smoothly curved, if there is significant concave curvature in a plane in the direction of travel, the soil tends to bind in the concavity.
It is desirable to have a paired row opener that works well without compromise in a broader range of soil conditions without fouling, and one which plants seed rows spaced widely while minimizing soil surface disturbance.
It is desirable to have these paired rows spaced sufficiently wide, closer to rows of adjacent tools, so there are not large spaces between rows planted by adjacent tools. Thus, during harvest there is an even stand of stubble to support a swath of cut crop above the ground for proper drying.
The prior art openers are generally quite narrow for seeding pairs of seed rows that are spaced quite closely. Seedbed forming portions of these planting tools generally operate within a space following a fertilizer furrow opening portion in which field trash has been cleared by the fertilizer opening portion. The seedbed forming portions therefor generally operate in soil that is substantially clear of field trash. An additional challenge in designing seedbed forming sections that form wider spaced paired rows is that a wider paired row opener will encounter field trash at it's outer edges which must not become caught on the opener, fouling it's operation.